8.2 and earlier build times

[Herbert Valerio Riedel]

On Wed, May 17, 2017 at 10:56 AM, Simon Peyton Jones via ghc-devs
<ghc-devs at haskell.org> wrote:
> That's great news!  Faster than GHC 7.8!   We should advertise this :-).

However, not everything is back to 7.8 levels  when looking at the
time-dimension, e.g. for regex-tdfa-1.2.2  (with reasonably similar
versions of dependencies):

GHC 7.8.4:

<<ghc: 71340383624 bytes, 1821 GCs, 159844888/430161152 avg/max bytes
residency (23 samples), 1221M in use, 0.00 INIT (0.00 elapsed), 41.12
MUT (45.55 elapsed), 16.85 GC (16.85 elapsed) :ghc>>

GHC 7.10.3:

<<ghc: 68219940408 bytes, 2275 GCs, 135800561/334469832 avg/max bytes
residency (30 samples), 934M in use, 0.001 INIT (0.001 elapsed),
41.251 MUT (45.513 elapsed), 18.519 GC (18.520 elapsed) :ghc>>

GHC 8.0.2:

<<ghc: 89544610040 bytes, 2301 GCs, 189183965/391103872 avg/max bytes
residency (29 samples), 1075M in use, 0.001 INIT (0.001 elapsed),
55.747 MUT (61.520 elapsed), 23.276 GC (23.278 elapsed) :ghc>>

GHC 8.2.1:

<<ghc: 115210990008 bytes, 6383 GCs, 116487828/234031864 avg/max bytes
residency (77 samples), 670M in use, 0.001 INIT (0.000 elapsed),
64.154 MUT (68.262 elapsed), 37.114 GC (37.077 elapsed) :ghc>>


So GHC 8.2.1 seems to have traded memory-in-use (significantly less
than 7.8) for compile-time (significantly more than 7.8).